Mercurial > hg
view mercurial/branchmap.py @ 46335:25be21ec6c65
share: rework config options to be much clearer and easier
Recently I implemented various boolean configs which control how to behave when
there is a share-safe mismatch between source and share repository. Mismatch
means that source supports share-safe where as share does not or vice versa.
However, while discussion and documentation we realized that it's too
complicated and there are some combinations of values which makes no sense.
We decided to introduce a config option with 4 possible values which
makes controlling and understanding things easier.
The config option `share.safe-mismatch.source-{not-}safe` can have
following 4 values:
* abort (default): error out if there is mismatch
* allow: allow to work with respecting share source configuration
* {up|down}grade-abort: try to {up|down}grade, if it fails, abort
* {up|down}grade-allow: try to {up|down}grade, if it fails, continue in allow
mode
I am not sure if I can explain 3 config options which I deleted right now in
just 5 lines which is a sign of how complex they became.
No test changes demonstrate that functionality is same, only names have changed.
Differential Revision: https://phab.mercurial-scm.org/D9785
author | Pulkit Goyal <7895pulkit@gmail.com> |
---|---|
date | Mon, 18 Jan 2021 21:37:20 +0530 |
parents | c4b792fa109e |
children | 1726a53a8494 799973a44c82 |
line wrap: on
line source
# branchmap.py - logic to computes, maintain and stores branchmap for local repo # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import struct from .node import ( bin, hex, nullid, nullrev, ) from . import ( encoding, error, pycompat, scmutil, util, ) from .utils import ( repoviewutil, stringutil, ) if pycompat.TYPE_CHECKING: from typing import ( Any, Callable, Dict, Iterable, List, Optional, Set, Tuple, Union, ) assert any( ( Any, Callable, Dict, Iterable, List, Optional, Set, Tuple, Union, ) ) subsettable = repoviewutil.subsettable calcsize = struct.calcsize pack_into = struct.pack_into unpack_from = struct.unpack_from class BranchMapCache(object): """mapping of filtered views of repo with their branchcache""" def __init__(self): self._per_filter = {} def __getitem__(self, repo): self.updatecache(repo) return self._per_filter[repo.filtername] def updatecache(self, repo): """Update the cache for the given filtered view on a repository""" # This can trigger updates for the caches for subsets of the filtered # view, e.g. when there is no cache for this filtered view or the cache # is stale. cl = repo.changelog filtername = repo.filtername bcache = self._per_filter.get(filtername) if bcache is None or not bcache.validfor(repo): # cache object missing or cache object stale? Read from disk bcache = branchcache.fromfile(repo) revs = [] if bcache is None: # no (fresh) cache available anymore, perhaps we can re-use # the cache for a subset, then extend that to add info on missing # revisions. subsetname = subsettable.get(filtername) if subsetname is not None: subset = repo.filtered(subsetname) bcache = self[subset].copy() extrarevs = subset.changelog.filteredrevs - cl.filteredrevs revs.extend(r for r in extrarevs if r <= bcache.tiprev) else: # nothing to fall back on, start empty. bcache = branchcache() revs.extend(cl.revs(start=bcache.tiprev + 1)) if revs: bcache.update(repo, revs) assert bcache.validfor(repo), filtername self._per_filter[repo.filtername] = bcache def replace(self, repo, remotebranchmap): """Replace the branchmap cache for a repo with a branch mapping. This is likely only called during clone with a branch map from a remote. """ cl = repo.changelog clrev = cl.rev clbranchinfo = cl.branchinfo rbheads = [] closed = set() for bheads in pycompat.itervalues(remotebranchmap): rbheads += bheads for h in bheads: r = clrev(h) b, c = clbranchinfo(r) if c: closed.add(h) if rbheads: rtiprev = max((int(clrev(node)) for node in rbheads)) cache = branchcache( remotebranchmap, repo[rtiprev].node(), rtiprev, closednodes=closed, ) # Try to stick it as low as possible # filter above served are unlikely to be fetch from a clone for candidate in (b'base', b'immutable', b'served'): rview = repo.filtered(candidate) if cache.validfor(rview): self._per_filter[candidate] = cache cache.write(rview) return def clear(self): self._per_filter.clear() def _unknownnode(node): """raises ValueError when branchcache found a node which does not exists""" raise ValueError('node %s does not exist' % pycompat.sysstr(hex(node))) def _branchcachedesc(repo): if repo.filtername is not None: return b'branch cache (%s)' % repo.filtername else: return b'branch cache' class branchcache(object): """A dict like object that hold branches heads cache. This cache is used to avoid costly computations to determine all the branch heads of a repo. The cache is serialized on disk in the following format: <tip hex node> <tip rev number> [optional filtered repo hex hash] <branch head hex node> <open/closed state> <branch name> <branch head hex node> <open/closed state> <branch name> ... The first line is used to check if the cache is still valid. If the branch cache is for a filtered repo view, an optional third hash is included that hashes the hashes of all filtered revisions. The open/closed state is represented by a single letter 'o' or 'c'. This field can be used to avoid changelog reads when determining if a branch head closes a branch or not. """ def __init__( self, entries=(), tipnode=nullid, tiprev=nullrev, filteredhash=None, closednodes=None, hasnode=None, ): # type: (Union[Dict[bytes, List[bytes]], Iterable[Tuple[bytes, List[bytes]]]], bytes, int, Optional[bytes], Optional[Set[bytes]], Optional[Callable[[bytes], bool]]) -> None """hasnode is a function which can be used to verify whether changelog has a given node or not. If it's not provided, we assume that every node we have exists in changelog""" self.tipnode = tipnode self.tiprev = tiprev self.filteredhash = filteredhash # closednodes is a set of nodes that close their branch. If the branch # cache has been updated, it may contain nodes that are no longer # heads. if closednodes is None: self._closednodes = set() else: self._closednodes = closednodes self._entries = dict(entries) # whether closed nodes are verified or not self._closedverified = False # branches for which nodes are verified self._verifiedbranches = set() self._hasnode = hasnode if self._hasnode is None: self._hasnode = lambda x: True def _verifyclosed(self): """ verify the closed nodes we have """ if self._closedverified: return for node in self._closednodes: if not self._hasnode(node): _unknownnode(node) self._closedverified = True def _verifybranch(self, branch): """ verify head nodes for the given branch. """ if branch not in self._entries or branch in self._verifiedbranches: return for n in self._entries[branch]: if not self._hasnode(n): _unknownnode(n) self._verifiedbranches.add(branch) def _verifyall(self): """ verifies nodes of all the branches """ needverification = set(self._entries.keys()) - self._verifiedbranches for b in needverification: self._verifybranch(b) def __iter__(self): return iter(self._entries) def __setitem__(self, key, value): self._entries[key] = value def __getitem__(self, key): self._verifybranch(key) return self._entries[key] def __contains__(self, key): self._verifybranch(key) return key in self._entries def iteritems(self): for k, v in pycompat.iteritems(self._entries): self._verifybranch(k) yield k, v items = iteritems def hasbranch(self, label): """ checks whether a branch of this name exists or not """ self._verifybranch(label) return label in self._entries @classmethod def fromfile(cls, repo): f = None try: f = repo.cachevfs(cls._filename(repo)) lineiter = iter(f) cachekey = next(lineiter).rstrip(b'\n').split(b" ", 2) last, lrev = cachekey[:2] last, lrev = bin(last), int(lrev) filteredhash = None hasnode = repo.changelog.hasnode if len(cachekey) > 2: filteredhash = bin(cachekey[2]) bcache = cls( tipnode=last, tiprev=lrev, filteredhash=filteredhash, hasnode=hasnode, ) if not bcache.validfor(repo): # invalidate the cache raise ValueError('tip differs') bcache.load(repo, lineiter) except (IOError, OSError): return None except Exception as inst: if repo.ui.debugflag: msg = b'invalid %s: %s\n' repo.ui.debug( msg % ( _branchcachedesc(repo), pycompat.bytestr( inst ), # pytype: disable=wrong-arg-types ) ) bcache = None finally: if f: f.close() return bcache def load(self, repo, lineiter): """fully loads the branchcache by reading from the file using the line iterator passed""" for line in lineiter: line = line.rstrip(b'\n') if not line: continue node, state, label = line.split(b" ", 2) if state not in b'oc': raise ValueError('invalid branch state') label = encoding.tolocal(label.strip()) node = bin(node) self._entries.setdefault(label, []).append(node) if state == b'c': self._closednodes.add(node) @staticmethod def _filename(repo): """name of a branchcache file for a given repo or repoview""" filename = b"branch2" if repo.filtername: filename = b'%s-%s' % (filename, repo.filtername) return filename def validfor(self, repo): """Is the cache content valid regarding a repo - False when cached tipnode is unknown or if we detect a strip. - True when cache is up to date or a subset of current repo.""" try: return (self.tipnode == repo.changelog.node(self.tiprev)) and ( self.filteredhash == scmutil.filteredhash(repo, self.tiprev) ) except IndexError: return False def _branchtip(self, heads): """Return tuple with last open head in heads and false, otherwise return last closed head and true.""" tip = heads[-1] closed = True for h in reversed(heads): if h not in self._closednodes: tip = h closed = False break return tip, closed def branchtip(self, branch): """Return the tipmost open head on branch head, otherwise return the tipmost closed head on branch. Raise KeyError for unknown branch.""" return self._branchtip(self[branch])[0] def iteropen(self, nodes): return (n for n in nodes if n not in self._closednodes) def branchheads(self, branch, closed=False): self._verifybranch(branch) heads = self._entries[branch] if not closed: heads = list(self.iteropen(heads)) return heads def iterbranches(self): for bn, heads in pycompat.iteritems(self): yield (bn, heads) + self._branchtip(heads) def iterheads(self): """ returns all the heads """ self._verifyall() return pycompat.itervalues(self._entries) def copy(self): """return an deep copy of the branchcache object""" return type(self)( self._entries, self.tipnode, self.tiprev, self.filteredhash, self._closednodes, ) def write(self, repo): try: f = repo.cachevfs(self._filename(repo), b"w", atomictemp=True) cachekey = [hex(self.tipnode), b'%d' % self.tiprev] if self.filteredhash is not None: cachekey.append(hex(self.filteredhash)) f.write(b" ".join(cachekey) + b'\n') nodecount = 0 for label, nodes in sorted(pycompat.iteritems(self._entries)): label = encoding.fromlocal(label) for node in nodes: nodecount += 1 if node in self._closednodes: state = b'c' else: state = b'o' f.write(b"%s %s %s\n" % (hex(node), state, label)) f.close() repo.ui.log( b'branchcache', b'wrote %s with %d labels and %d nodes\n', _branchcachedesc(repo), len(self._entries), nodecount, ) except (IOError, OSError, error.Abort) as inst: # Abort may be raised by read only opener, so log and continue repo.ui.debug( b"couldn't write branch cache: %s\n" % stringutil.forcebytestr(inst) ) def update(self, repo, revgen): """Given a branchhead cache, self, that may have extra nodes or be missing heads, and a generator of nodes that are strictly a superset of heads missing, this function updates self to be correct. """ starttime = util.timer() cl = repo.changelog # collect new branch entries newbranches = {} getbranchinfo = repo.revbranchcache().branchinfo for r in revgen: branch, closesbranch = getbranchinfo(r) newbranches.setdefault(branch, []).append(r) if closesbranch: self._closednodes.add(cl.node(r)) # new tip revision which we found after iterating items from new # branches ntiprev = self.tiprev # Delay fetching the topological heads until they are needed. # A repository without non-continous branches can skip this part. topoheads = None # If a changeset is visible, its parents must be visible too, so # use the faster unfiltered parent accessor. parentrevs = repo.unfiltered().changelog.parentrevs for branch, newheadrevs in pycompat.iteritems(newbranches): # For every branch, compute the new branchheads. # A branchhead is a revision such that no descendant is on # the same branch. # # The branchheads are computed iteratively in revision order. # This ensures topological order, i.e. parents are processed # before their children. Ancestors are inclusive here, i.e. # any revision is an ancestor of itself. # # Core observations: # - The current revision is always a branchhead for the # repository up to that point. # - It is the first revision of the branch if and only if # there was no branchhead before. In that case, it is the # only branchhead as there are no possible ancestors on # the same branch. # - If a parent is on the same branch, a branchhead can # only be an ancestor of that parent, if it is parent # itself. Otherwise it would have been removed as ancestor # of that parent before. # - Therefore, if all parents are on the same branch, they # can just be removed from the branchhead set. # - If one parent is on the same branch and the other is not # and there was exactly one branchhead known, the existing # branchhead can only be an ancestor if it is the parent. # Otherwise it would have been removed as ancestor of # the parent before. The other parent therefore can't have # a branchhead as ancestor. # - In all other cases, the parents on different branches # could have a branchhead as ancestor. Those parents are # kept in the "uncertain" set. If all branchheads are also # topological heads, they can't have descendants and further # checks can be skipped. Otherwise, the ancestors of the # "uncertain" set are removed from branchheads. # This computation is heavy and avoided if at all possible. bheads = self._entries.setdefault(branch, []) bheadset = {cl.rev(node) for node in bheads} uncertain = set() for newrev in sorted(newheadrevs): if not bheadset: bheadset.add(newrev) continue parents = [p for p in parentrevs(newrev) if p != nullrev] samebranch = set() otherbranch = set() for p in parents: if p in bheadset or getbranchinfo(p)[0] == branch: samebranch.add(p) else: otherbranch.add(p) if otherbranch and not (len(bheadset) == len(samebranch) == 1): uncertain.update(otherbranch) bheadset.difference_update(samebranch) bheadset.add(newrev) if uncertain: if topoheads is None: topoheads = set(cl.headrevs()) if bheadset - topoheads: floorrev = min(bheadset) ancestors = set(cl.ancestors(newheadrevs, floorrev)) bheadset -= ancestors bheadrevs = sorted(bheadset) self[branch] = [cl.node(rev) for rev in bheadrevs] tiprev = bheadrevs[-1] if tiprev > ntiprev: ntiprev = tiprev if ntiprev > self.tiprev: self.tiprev = ntiprev self.tipnode = cl.node(ntiprev) if not self.validfor(repo): # cache key are not valid anymore self.tipnode = nullid self.tiprev = nullrev for heads in self.iterheads(): tiprev = max(cl.rev(node) for node in heads) if tiprev > self.tiprev: self.tipnode = cl.node(tiprev) self.tiprev = tiprev self.filteredhash = scmutil.filteredhash(repo, self.tiprev) duration = util.timer() - starttime repo.ui.log( b'branchcache', b'updated %s in %.4f seconds\n', _branchcachedesc(repo), duration, ) self.write(repo) class remotebranchcache(branchcache): """Branchmap info for a remote connection, should not write locally""" def write(self, repo): pass # Revision branch info cache _rbcversion = b'-v1' _rbcnames = b'rbc-names' + _rbcversion _rbcrevs = b'rbc-revs' + _rbcversion # [4 byte hash prefix][4 byte branch name number with sign bit indicating open] _rbcrecfmt = b'>4sI' _rbcrecsize = calcsize(_rbcrecfmt) _rbcnodelen = 4 _rbcbranchidxmask = 0x7FFFFFFF _rbccloseflag = 0x80000000 class revbranchcache(object): """Persistent cache, mapping from revision number to branch name and close. This is a low level cache, independent of filtering. Branch names are stored in rbc-names in internal encoding separated by 0. rbc-names is append-only, and each branch name is only stored once and will thus have a unique index. The branch info for each revision is stored in rbc-revs as constant size records. The whole file is read into memory, but it is only 'parsed' on demand. The file is usually append-only but will be truncated if repo modification is detected. The record for each revision contains the first 4 bytes of the corresponding node hash, and the record is only used if it still matches. Even a completely trashed rbc-revs fill thus still give the right result while converging towards full recovery ... assuming no incorrectly matching node hashes. The record also contains 4 bytes where 31 bits contains the index of the branch and the last bit indicate that it is a branch close commit. The usage pattern for rbc-revs is thus somewhat similar to 00changelog.i and will grow with it but be 1/8th of its size. """ def __init__(self, repo, readonly=True): assert repo.filtername is None self._repo = repo self._names = [] # branch names in local encoding with static index self._rbcrevs = bytearray() self._rbcsnameslen = 0 # length of names read at _rbcsnameslen try: bndata = repo.cachevfs.read(_rbcnames) self._rbcsnameslen = len(bndata) # for verification before writing if bndata: self._names = [ encoding.tolocal(bn) for bn in bndata.split(b'\0') ] except (IOError, OSError): if readonly: # don't try to use cache - fall back to the slow path self.branchinfo = self._branchinfo if self._names: try: data = repo.cachevfs.read(_rbcrevs) self._rbcrevs[:] = data except (IOError, OSError) as inst: repo.ui.debug( b"couldn't read revision branch cache: %s\n" % stringutil.forcebytestr(inst) ) # remember number of good records on disk self._rbcrevslen = min( len(self._rbcrevs) // _rbcrecsize, len(repo.changelog) ) if self._rbcrevslen == 0: self._names = [] self._rbcnamescount = len(self._names) # number of names read at # _rbcsnameslen def _clear(self): self._rbcsnameslen = 0 del self._names[:] self._rbcnamescount = 0 self._rbcrevslen = len(self._repo.changelog) self._rbcrevs = bytearray(self._rbcrevslen * _rbcrecsize) util.clearcachedproperty(self, b'_namesreverse') @util.propertycache def _namesreverse(self): return {b: r for r, b in enumerate(self._names)} def branchinfo(self, rev): """Return branch name and close flag for rev, using and updating persistent cache.""" changelog = self._repo.changelog rbcrevidx = rev * _rbcrecsize # avoid negative index, changelog.read(nullrev) is fast without cache if rev == nullrev: return changelog.branchinfo(rev) # if requested rev isn't allocated, grow and cache the rev info if len(self._rbcrevs) < rbcrevidx + _rbcrecsize: return self._branchinfo(rev) # fast path: extract data from cache, use it if node is matching reponode = changelog.node(rev)[:_rbcnodelen] cachenode, branchidx = unpack_from( _rbcrecfmt, util.buffer(self._rbcrevs), rbcrevidx ) close = bool(branchidx & _rbccloseflag) if close: branchidx &= _rbcbranchidxmask if cachenode == b'\0\0\0\0': pass elif cachenode == reponode: try: return self._names[branchidx], close except IndexError: # recover from invalid reference to unknown branch self._repo.ui.debug( b"referenced branch names not found" b" - rebuilding revision branch cache from scratch\n" ) self._clear() else: # rev/node map has changed, invalidate the cache from here up self._repo.ui.debug( b"history modification detected - truncating " b"revision branch cache to revision %d\n" % rev ) truncate = rbcrevidx + _rbcrecsize del self._rbcrevs[truncate:] self._rbcrevslen = min(self._rbcrevslen, truncate) # fall back to slow path and make sure it will be written to disk return self._branchinfo(rev) def _branchinfo(self, rev): """Retrieve branch info from changelog and update _rbcrevs""" changelog = self._repo.changelog b, close = changelog.branchinfo(rev) if b in self._namesreverse: branchidx = self._namesreverse[b] else: branchidx = len(self._names) self._names.append(b) self._namesreverse[b] = branchidx reponode = changelog.node(rev) if close: branchidx |= _rbccloseflag self._setcachedata(rev, reponode, branchidx) return b, close def setdata(self, branch, rev, node, close): """add new data information to the cache""" if branch in self._namesreverse: branchidx = self._namesreverse[branch] else: branchidx = len(self._names) self._names.append(branch) self._namesreverse[branch] = branchidx if close: branchidx |= _rbccloseflag self._setcachedata(rev, node, branchidx) # If no cache data were readable (non exists, bad permission, etc) # the cache was bypassing itself by setting: # # self.branchinfo = self._branchinfo # # Since we now have data in the cache, we need to drop this bypassing. if 'branchinfo' in vars(self): del self.branchinfo def _setcachedata(self, rev, node, branchidx): """Writes the node's branch data to the in-memory cache data.""" if rev == nullrev: return rbcrevidx = rev * _rbcrecsize if len(self._rbcrevs) < rbcrevidx + _rbcrecsize: self._rbcrevs.extend( b'\0' * (len(self._repo.changelog) * _rbcrecsize - len(self._rbcrevs)) ) pack_into(_rbcrecfmt, self._rbcrevs, rbcrevidx, node, branchidx) self._rbcrevslen = min(self._rbcrevslen, rev) tr = self._repo.currenttransaction() if tr: tr.addfinalize(b'write-revbranchcache', self.write) def write(self, tr=None): """Save branch cache if it is dirty.""" repo = self._repo wlock = None step = b'' try: # write the new names if self._rbcnamescount < len(self._names): wlock = repo.wlock(wait=False) step = b' names' self._writenames(repo) # write the new revs start = self._rbcrevslen * _rbcrecsize if start != len(self._rbcrevs): step = b'' if wlock is None: wlock = repo.wlock(wait=False) self._writerevs(repo, start) except (IOError, OSError, error.Abort, error.LockError) as inst: repo.ui.debug( b"couldn't write revision branch cache%s: %s\n" % (step, stringutil.forcebytestr(inst)) ) finally: if wlock is not None: wlock.release() def _writenames(self, repo): """ write the new branch names to revbranchcache """ if self._rbcnamescount != 0: f = repo.cachevfs.open(_rbcnames, b'ab') if f.tell() == self._rbcsnameslen: f.write(b'\0') else: f.close() repo.ui.debug(b"%s changed - rewriting it\n" % _rbcnames) self._rbcnamescount = 0 self._rbcrevslen = 0 if self._rbcnamescount == 0: # before rewriting names, make sure references are removed repo.cachevfs.unlinkpath(_rbcrevs, ignoremissing=True) f = repo.cachevfs.open(_rbcnames, b'wb') f.write( b'\0'.join( encoding.fromlocal(b) for b in self._names[self._rbcnamescount :] ) ) self._rbcsnameslen = f.tell() f.close() self._rbcnamescount = len(self._names) def _writerevs(self, repo, start): """ write the new revs to revbranchcache """ revs = min(len(repo.changelog), len(self._rbcrevs) // _rbcrecsize) with repo.cachevfs.open(_rbcrevs, b'ab') as f: if f.tell() != start: repo.ui.debug( b"truncating cache/%s to %d\n" % (_rbcrevs, start) ) f.seek(start) if f.tell() != start: start = 0 f.seek(start) f.truncate() end = revs * _rbcrecsize f.write(self._rbcrevs[start:end]) self._rbcrevslen = revs